FUSARIUM. 



[ 283 ] 



GAMMARUS. 



F. Reinhardtii, E. (PI. 34. fig. 34 ; fig. 33, 

 teeth). Body fusiform, truncated in front ; 

 foot elongate, cylindrical ; toes two, short ; 

 length 1-120". 



FonndcreeYtii^g upon Laomedeageniculata. 



F. gihba. Body oblong, slightly com- 

 pressed, dorsally convex, ventrally flat ', 

 toes styliform, half as long as the body; 

 length 1-96". Aquatic. 



BiBL. Ehrenb, J/i/ms. p. 419 ; Dujardin, 

 Infus. p. 648; Gosse, Ann. Nat. Hist. 1851. 

 viii. p. 199. 



FUSARIUM, Lk.— A genus of Stilbacei 

 (Hji^homycetous Fungi), not very satis- 

 factorily distinguished from Fusisporium, 

 but having a firm cellular, pulvinate, fleshy 

 stroma, upon which the spores are borne on 

 distinct sporophores, glued together into an 

 erumpent discoid stratum. F. tremelloides 

 is common, forming roundish orange-red 

 spots on decaying nettle-stems. F. roseum 

 forms little gregarious red dots on the stems 

 of beans, Jerusalem artichokes, and other 

 plants. 



BiBL. Berk. Hook. Brit. Flora, ii. pt. 2. 

 p. 355 ; Fries, System. Myc. iii. 469, Summa 

 Veg. AT2 ; Greville, Sc. Crypt. Flora, pi. 20; 

 Fresenius, Beitr. zur Mycologie, Heft 1. 

 p. 35. 



FUSIDIUM, Lk. See Fusisporium. 



FUSISPORIUM, Lk.— A genus of Sepe- 

 doniei (Hyphomycetous Fungi), growing 

 upon vegetable substances, often when de- 

 caying, forming either a kind of mildew or 

 subsequently an extensive gelatinous stra- 

 tum, bearing spindle-shaped 

 spores (fig. 27O). The myce- 

 lium is composed of very de- 

 licate filaments, which are 

 generally evanescent, and 

 partially dissolve so as to 

 glue the fallen spores into a 

 mass upon a tremelloid ma- 

 trix. Several species are of a 

 rose-colour. The genus Fu- 

 sidium, Lk., is separated by 

 some authors, and placed 

 among the Mucedines, on account of its 

 evanescent mycelium and the absence of a 

 stroma, from Fusisporium, Lk., in which 

 the mycelium is converted into an efiiised 

 gelatinous stratum ; but the distinction ap- 

 pears unimportant. Numerous species are 

 recorded as British. F. atrovirens is a de- 

 structive mildew on onions. F. griseum is 

 common on dead leaves. F.foeni is remark- 

 able for forming large orange -red patches, 

 many feet in width. The genus Fusarium 



Fusisporium. 



Spores. Magn. 



400 diams. 



differs from this in the presence of a discoid 

 stroma. 



BiBL. Berk. Hook. Brit. Flora, ii. pt. 2. 

 p. 251, Ann. Nat. Hist. vi. p. 438. pi. 14. 

 fig. 28, 2 ser. vii. p. 1/8 ; Fries, Syst. Myc. 

 iii. p. 442, Summa Veget. p. 473 ; Greville, 

 Sc. Crypt. Flora, pi. 102. figs. 1 & 2. 



G. 



GALLIONELLA, Bory. = Melosira, 



Agardh . Gall, ferrugin ea = DidymoJielixfer. 



GALLS. — These are abnormal growths, 

 tumours as they might be called, produced 

 upon or in vegetables by the action of ani- 

 mals, especially insects of the family Hyme- 

 noptera. They are supposed to arise from the 

 irritation caused by a poisonous liquid dis- 

 charged into the orifice made by the insect 

 for the introduction of its egg. At all events 

 a convergence of the nutritive juices towards 

 the wound takes place, whence results a kind 

 of hypertrophy of the tissues, and frequently 

 the accumulation of such substances as starch 

 in the cells. The forms may be regular or 

 irregular; most of them are characteristic, 

 as for example, the well-known nut-gall, the 

 oak-apple, the bedeguar of the rose, &c. 

 Both cellular and vascular structures contri- 

 bute to form the substance of galls. We 

 cannot enter into their minute structure 

 here, but refer to an elaborate paper by Dr. 

 Lacaze-Duthiers. 



BiBL. Lacaze-Duthiers, Ann. des Sc. nat. 

 3 ser. xix. 2/3, where also the earlier litera- 

 ture is given. 



GALUMNA, Heyden, Gervais. — A genus 

 of Ai'achnida, of the order Acarina, and fa- 

 mily Oribatea. 



Char. Abdomen subglobular, depressed; 

 sides of the pseudo-thorax forming a salient 

 or wing-like angle; legs of moderate length. 



This genus approximates to Belba. 



The three species, the bodies of which are 

 of a blackish, blackish-chestnut, or ash- 

 coloiu', are found on mosses. 



BiBL. Walckenaer, Arachnid. (Gervais); 

 Hermann, Mem. Apter. p. 91 ; Koch, 

 Deutschl. Crustac. &c. 



GAMMARUS, Latr.— A genus of Crus- 

 tacea, of the order Amphipoda, and family 

 Gammarina. 



The searcher for the freshwater Diatoma- 

 cese will surely meet \^ith Gammarus pulex, 

 the freshwater shrimp, in muddy brooks and 

 streams. It attains a length of about 1-2", 

 and moves its cm'ved body through the water 

 by means of its caudal appendages, fre- 



